High Rate Packet Data (HRPD) standard (aka EV-DO), as well as other recently defined high-speed wireless data technologies, were designed to maximize the air interface transmission efficiency for a small number of active users with heavy data volume transactions. The technology employs multiple overhead/feedback channels to optimize the traffic channel performance.
However, as the HRPD Rev.0/RevA system deployment continues, it has been observed that the traffic pattern significantly deviates from the above assumptions. That is, most of the data applications that prevail in wireless networks have short data bursts and quite long inter-burst intervals, such as generated by short message services, rich presence applications, etc. This pattern is further magnified by the emergence of applications with automated communication between a wireless device and the network. These applications often do not require end-user intervention and are based on an “always-on” concept involving intermittent messaging, such as application status notifications and keep-alive messages.
These application may be referred to as “chatty applications”, meaning that the applications frequently access the network, but each access only generates a small amount of data traffic.
With chatty applications dominating the wireless markets, the achieved air interface HRPD performance is severely degraded due to a mismatch with the original design philosophy. Instead of a small number of users accessing the network at a time, many more users are seen trying to access the network. This significantly increases the access channel loading and causes high RF interference on the reverse link due to access channel overload. Instead of a small number of active users maintaining their RF connections, the network opens a large number of connections, causing connection overflow and call blocking. In addition, since each connection maintains associated overhead/feedback channels, this creates a high RF resource usage just to support those overhead channels. Still further, instead of large data volumes that take advantage of efficient air transmission, each chatty application connection only generates a small amount of data, and does so intermittently, for the lifetime of the connection. Namely, the connection remains idle most of the time. This makes the connection utilization very low.